The official Arsenal site has put up a page listing, without explanation, the eligibility for various competitions of our new signings.

Abou Diaby is ok for all competitions. As we explained previously, the fact that he has played in the UEFA Cup this season for Auxerre doesn't matter. A club can register 3 new players with UEFA in January, and one of them is allowed to have played in Europe previously in the same season, so long as it was in a different UEFA competition.

Emmanuel Adebayor, however, cannot play in the Champs League, because he played in that competition for Monaco already this season (Monaco came in at the 3rd qualifying round stage, where they lost 3-2 on aggregate to Real Betis - Adebayor played in both legs).

Both the above players are fine of course for the domestic cups, and Diaby could well feature in tonight's match against Wigan).

Theo Walcott, however, can play in the Champs League but in neither the FA Cup nor the League Cup, having played for Southampton in those competitions already this season. This is
a bit shame, because the cup games would have been the ideal opportunities to give him first taste of playing for the Gunners.

Arsenal's page does not mention our other new signing, Mart Poom. Mart is eligible for all competitions, having played for no-one for 6 months.